Method of securing spark-plug electrodes to conducting heads



W. S. THOMAS.

METHOD OF SECURING SPARK PLUG ELECTRODES T0 CONDUCTING HEADS.

APPLICATION FILED NOV. 16, 1920.

1,416,248, Patented Ma 16, 1922 A )jya uuireo stares rarest or ies WILMAM S. THOMAS, 013 ROSELLE PARK, NEW JERSEY, ASSIGNOR TO THOMAS SPARK IPL'UG- 00., F ROSELLE PARK, NEW JERSEY.

R'IETHQD 015 SECURING: SPARK-PLUG ELECTRODES T0 CONDUCTING- HEADS.

Application filed November 16, 1920.

T 0 all whom it may concern:

Be it known that 1, WILLIAM S. THOMAS, a citizen of the United States, residing at Roselle Park, in the county -of Elizabeth and State of New Jersey, have invented certain new and useful Improvements in Method of Securing SparlcPlug Electrodes to Conducting Heads, of which the following is a specification.

Great difliculty is experienced in the manufacture of spark plugs, for use in connection with internal combustion engines, in the manner of connecting the usual central electrode to the head to which the electric wire is connected.

The usual method of securing such electrodes to the heads is to solder or braze the electrode to the head but this means has not been entirely successful since the electrodes due to the heat very often work loose and a poor contact is formed between the electrode head and the electrode rod. It is of course obvious that any means of securing elements becoming separated.

One object of my invention is to secure the electrode rod to the conducting head of a spark plug in such manner that the rod will not accidentally become loose.

Another object is that the means of securing the rod to the head will provide a good electric connection between the two elements.

A further object is to facilitate the con nection of said elements so that the electrode can be quickly and cheaply manufactured.

These objects, and other advantageous ends which will be described hereinafter, I attain in the following manner, reference beinghad to the accompanying drawings in which Figure 1 is an enlarged elevation, partly in section, showing an electrode made in accordance with my present invention,

Figures 2, 3 and 4L are elevations, partly in section, showing my improved method of securing the electrode rod to the head, said figures illustrating the various stages followed in my improved method,

Figure 5 is an enlarged fragmentary section illustrating the action of the parts in securing the electrode rod to the head, and

Specification of Letters Patent.

Serial No. 424,434.

struction of this head may be made of any of the well known forms and does not in itself constitute my invention only in respects hereinafter described.

The stem 8 is used to receive a securing nut for binding the electric conduit wire to the head so as to carry the current to the plug. The head 7 has a cavity 10 bored or otherwise formed therein and is adapted to receive one end of an electrode rod 11.

In carrying out my improved method of attaching the electrode rod to the head 7 I preferably place the flange 9 upon a base structure 12 as shown in Figure 2 so that the screw threaded stem 8 depends downwardly leaving the body portion 13 of the head in an upright position; said supporting structure having a hole 14 to receive the stem 8. After the head is thus mounted on the supporting structure 12 the electrode rod is forced downwardly into the cavity 10 so as to produce a tight fit after which a tube 15 is slid over the electrode rod in a manner shown in F igure 3;

The tube 15 at its lower end has a downwardly tapering frusto-conical surface 16 which intercepts an upwardly tapering frusto-conical surface 17 which leads to the bottom of the bar 18 of the tube 15. Thus the tube 15 includes an annularly extending cutting edge 19 of greater diameter than the diameter of the electrode rod which extends through the bore 18 and into the cavity 10'. The tube 15 is preferably made of such length that its top end, after being slid upon the electrode rod 11, is above the outer end of the electrode rod 11 when the. tube is in the position shown in Figure 3 and resting on the top surface 20 of the body portion 13 of the head '7.

By forcing the tube 15 downwardly, such for example as with the blow of a hammer or other pressure device, the cutting edge 19 of the tube will be forced into the meted of the body portion 13 of the head 7 and a part/21 of such metal will he forced laterally into the electrode rod and thereby securely connect the electrode rod to the body portion 13 of the head 7. The material of the body portion 13 of the head 7 is preferably made of harder metal than that from which the electrode rod 11 is made so that the portion 21 of the metal of the head will indent the metal of the electrode rod and prevent relative movement between the electrode rod and the head.

In actual practice it has been found that practically no condition to which a spark plug of this character is subjected is capable of loosening or disconnecting an electrode rod which is attached to a conducting head in the manner above described.

While I have described my invention as being carried out in a specific manner, it will be understood that the various steps of my improved method may be changed without departing from the spirit of my invention and hence I do not limit myself to the precise method set forth, but consider that I am at liberty to make such changes and alterations as fairly come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is l. The herein described process of securing an electrode rod to a head which consists in providing said head with a cavity, then inserting a portion of the electrode rod in said cavity and finally forcing a portion of the material of said head laterally so as to indent the material of said electrode rod.

2. The herein described process of securing an electrode rod to a head which consists in providing said head with a cavity,.

then inserting a portion of the electrode rod in said cavity and finally forcing an annular portion of the material of said head laterally to indent the material of said electrode rod.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM S. THOMAS.

Witnesses:

ELIZABETH GARBE, (lHAs. E. Por'rs. 

